Prenatal Exposure to Nicotine May Increase Risk of Nicotine Susceptibility Later in Life

MedicalResearch.com Interview with:

Davide Dulcis, PhDAssociate ProfessorDepartment of Psychiatry, UCSD School of MedicineUniversity of California, San DiegoLa Jolla, CA 92093-0603

Dr. Dulcis

Davide Dulcis, PhD
Associate Professor
Department of Psychiatry, UCSD School of Medicine
University of California, San Diego
La Jolla, CA 92093-0603

MedicalResearch.com: What is the background for this study? What are the main findings? 

Response: Previous studies in humans have shown that pre-natal and early life exposure to nicotine can lead to altered children behavior and propensity for drug abuse, but the precise mechanisms involved are still unclear.

In this pre-clinical study we showed how nicotine “primes” neurons of the mouse brain’s reward center for a fate they normally would not have taken, making them more susceptible to the effects of nicotine when the animals are again exposed to nicotine later in life, said Dr. Benedetto Romoli, first author of the research article.   Continue reading

Which Brain Circuits Determine Maternal Behavior?

MedicalResearch.com Interview with:
“Mother and Child” by Mary Cassatt (American, Pittsburgh, Pennsylvania 1844–1926 Le Mesnil-Théribus, Oise) via The Metropolitan Museum of Art is licensed under CC0 1.0Yi-Ya Fang

NYU School of Medicine
Dayu Lin, PhD
Neuroscience Institute, New York University Langone School of Medicine,  Department of Psychiatry,
Center for Neural Science
New York, NY

Response: Maternal behaviors are essential for survival of offspring across mammalian species. In rodents, mothers show several characteristic pup caring behaviors including grooming pups, crouching over pups and approaching and retrieving pups. Decades of research has been trying to understand how the neural circuit is wired to generate these elaborate maternal behaviors. Medial preoptic area (MPOA), which is located at anterior part of hypothalamus, has been indicated to be important for maternal behaviors. Many studies consistently found deficits in maternal behaviors after damaging the MPOA. To dissect the maternal circuits in the brain, we looked into the properties of the Esr1+ cells.

In this study, we identify estrogen receptor α (Esr1) expressing cells in MPOA as key mediators of pup approach and retrieval. We focused on Esr1 (Esr1) expressing cells in the MPOA since estrogen has been shown to facilitate maternal behaviors, presumably through its action of estrogen sensing cells. We found that reversible inactivation of MPOA Esr1+ cells impairs maternal behaviors whereas optogenetic activation of MPOA Esr1+ cells induces immediate pup retrieval. Additionally, we found that MPOA Esr1+ cells are preferentially activated during maternal behaviors, and the cell responses changed across reproductive states. Tracing studies revealed that MPOA Esr1+ cells project strongly to ventral tegmental area (VTA), a region that has been indicated in motivation and reward. Specifically, MPOA Esr1+ cells provide strong inhibitory inputs preferentially to the GABAergic cells in the VTA, which in turn could disinhibit the dopaminergic cells.  VTA dopaminergic cells are highly activated during maternal behaviors.

Altogether, our study provides new insight into the neural circuit that generates maternal behaviors.

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